I actually wrote a fanfic on a plane two years ago about one of these. (I will not post it, since it is bad.)
Essentially, there are villages in Pennsylvania's Pocono Mountains, highly insular and protected by layers of walls. They have cleansers whose job it is to expand the uninfected areas so that the people can go hunting without the risk of getting the "rot", and maybe someday expand the village. The people, at least the ones in the village the fanfic focuses on, are mainly Protestant Christian, which affects their magic. I thought it would be cool to see more mages like Pastor Anne.
One twelve-year-old boy begs to take a trip with the cleansers (he likes fire) into the middle of the cleansed area. Upon reaching it, he wanders out and meets a giant. The giant says some very spooky things into his head, then charges him. He escapes by running super fast and then standing still and staying silent inside a hole, AYO, and after getting a stern talking-to, eventually gets to start his mage training.